Since you don't have the game for either platform yet, I would go for the PC version.
As already stated you can set the graphics higher settings higher on a PC than on a console. Additionally, console games are generally rendered at 720p an then it is stretched to fit the full screen of a HDTV or monitor. Stretching causes a drop in visual quality. The higher the resolution 720p is stretch to, the worse it would look compared to playing the game at it's actual resolution.
Below are benchmarks for Deus EX Human Revolution @ 1680 x 1050 resolution with the highest graphic settings. Additionally, it includes DX11 effects something that the PS3 or Xbox 360 version does not have. The Radeon HD 6670 is not part of the benchmarks, but it...